1. The Terrakin are supposed to be humanity, though they don't entirely look the part.

2. There's an SR1 portrait mod on the Workshop, including a pretty good human portrait. If this is not an option due to your having a non-Steam version of the game, I can only point you in the direction of the Alternate Balance Expansion Mod - it contains a modified form of Vincent's mod. (It also contains a bunch of other stuff, so ABEM is not necessarily a good choice for a new player. Way much more to learn.)

If you're interested in ABEM, you can get ABEM 0.3.0 from ModDB, GitHub, or the Steam Workshop, where you can choose between 0.3.0 and the 0.4.0 beta.